We have proposed a course of research involving the use of 1,3-dipolar cyclo-addition reactions to generate a host of widely divergent classes of alkaloids. Thus, we have suggested entries into the Nuphar, Lythraceae, Senecio, Cephalotaxus, Tropane, piperidine, perhydro-9b-azaphenalene, Elaeocarpus, and related alkaloidal families. We plan to utilize the stereoselectivity and regioselectivity of nitrone cycloadditions to facilitate our approaches to the desired natural products. In addition, we propose to explore the chemistry of nitrones and their cycloadducts (isoxazolidines) in an effort to enhance the synthetic utility of these methods. The target molecules exhibit a wide range of physiological activity, including anti-mitotic, bateriostatic, bacteriocidal, restorative, relaxative, anti-neoplastic, and toxic behavior. We plan to submit all relevant intermediates for the appropriate physiological screens.